The treatment of dental caries in all manner of decay possibilities is done with the objective of removing undesired layers of active decay, minimizing future bacterial intrusions, and filling the excavated site with appropriate fillings. Unfortunately, dentists employing the accepted method of high-speed drilling will inevitably and consistently remove far more undamaged dentin than is desirable. Secondly, they will introduce by the very nature of drill action a layer of potential bacterial corruption called the smear zone. This is where the rotating and grinding of the drill tip ceases to dig further, leaving a rough landscape which dentists must attempt to polish away. Mechanically drilling away caries and tooth structure is a remedy to a problem, but a process found lacking in many ways.
The use of abrasive air or fluid driven methodology to resolve medical problems is centered on anatomical features undergoing gross exposure to reducing substances flung against them. Any attempt in the prior art to limit fluid bounce or splash is centered on physical barrier shields to contain rebounding discharges. It is directly due to damage to peripheral tissue that the use of pressurized fluids in dental applications is primarily used for low psi cleaning applications, rather than cavity care. A liquid jet stream brings a force of impact against dental structure that is concentrated in the center, with less proportional force the further from this center that is measured. Although capable of cleaning surfaces, this singular type of stream is not optimal for evenly wearing away dental structures in the zone hit by the fluid. Thus in these examples the outer edge of the strike zone (relative to the center) is not removed with a similar depth. With reducing elements included, the result is a curved-wall crater rather than a flat and round pill-box style excavation.